1. Field of the Invention
The present invention relates to a reactive dye.
2. Description of the Prior Art
Hitherto, reactive dyes are frequently used in a concentrated aqueous liquid form because such the liquid form, like other species of dyes, is not dusty and easy to handle in weighing, transportation, dissolution, etc. In order to further improve the storage stability of such the liquid form, various treatments such as desalting, addition of auxiliaries (e.g. .epsilon.-caprolactam, polyvinylpyrrolidone), etc. are applied. However, in the case of the liquid composition of a reactive dye which is represented by the formula (Ia) as a free acid, ##STR2## wherein R represents --NH.sub.2, or --NHC.sub.2 H.sub.4 SO.sub.3 H, and commercially used as a dye in the form of a sodium or potassium salt, desired improvements in quality, for example prevention of the liquid composition from crystallization during prolonged storage at a low to room temperature, prevention of the liquid composition from freezing, etc. cannot be attained by mere desalting and addition of auxiliaries. Particularly, when the dye concentration is high, the difficulty becomes large.
Consequently, as to the reactive dye represented by the foregoing formula (Ia), it is desired to develop such a new dye form as to provide a concentrated aqueous liquid composition which will not freeze, nor produce dye crystals even by prolonged storage at a low to room temperature (about -10.degree. C. to 30.degree. C).